Preliminary investigation of voice onset time production in persons with dysphagia

The purpose of this study was to determine whether voice onset time (VOT) v alues of persons with dysphagia differed from those of a person with normal swallow function. Five male subjects with dysphagia (average age = 80.6 ye ars) and a control subject (age = 79 years) read 18 consonant-vowel-consona nt words in quasi-random order. These syllables began with the voiced and v oiceless cognates from the three stop places of articulation (i.e., bilabia l, alveolar, and velar). These consonants were followed by the vowels /i/, /a/, and /u/. Digital audio tape recordings were performed and speech was d igitized onto disk. Measurements were completed using BLISS software (Mertu s J: BLISS User's Manual. Providence: Department of Cognitive and Linguisti c Sciences, Brown University, 1989) implemented on a 486 microcomputer. Ave rages and standard deviations of the VOT measures for the six stop consonan ts were compared between the two experimental groups. For the dysphagic spe akers, average VOT values for voiceless stops were shorter, and there were larger negative VOT values for voiced stops. Standard deviations for the VO T productions pf the dysphagic subjects were smaller. Statistical compariso ns showed significant differences between individual dysphagic speakers and the normal control for three of the five subjects. These preliminary data suggest that dysphagia affects the fine motor control required for accurate VOT production in speech.